Many metal and organic resin components for vehicle engines, machinery, and other mechanical devices require as one of the steps in manufacture, a deflashing or deburring operation. In the case of molded resin parts, such as those made of phenolic or like hard resin, it is principally a matter of removing any flash from the molding operation whereas in the case of machined metal parts it is a matter of removing any burrs left from imperfections in the machining. Such deflashing and deburring operations are especially important for components which are required to seat or mate closely with other components during operation. Valves and valve seats are examples. The objective in the deflashing and deburring operation is to fully remove the flash and burrs without at the same time in any way deteriorating the surface finish of the components. Essential for efficiency is that the deburring and deflashing be accomplished rapidly and at low cost. It has become conventional to perform such deflashing and deburring operations by blasting such components with a blasting media, i.e. by forcefully impinging against the components small, hard pellets. The efficiency of such an operation is dependent on the physical characteristics of the blasting media. That is, the pellets of the blasting media must have a shape and hardness sufficient to effectively remove the flash and burrs but yet not such as to cause, under the force of the impingement, distortion or other deterioration to the surface or surface finish of the components. Still further, the pellets of the blasting media should ideally be extremely tough so that they can withstand repeated cycling--repeated impingements against the components--without significant distortion to their shape, cracking or excessive wear. As in virtually all situations where both hardness and toughness are required, compromise has been necessary. That is, hardness is at the expense of toughness and toughness is at the expense of hardness.
Prior to the present invention it was already known to use a blasting media of organic resin, such as nylon or polycarbonate resin, for deflashing and deburring operations. However, choice of the particular organic resin used has involved the aforesaid compromise, i.e. long media life at the expense of deburring and deflashing effectiveness and vice versa.